A two-locus selection hypothesis for Duchenne Muscular Dystrophy

Three hypotheses to explain the incidence and familial structure of Duchenne Muscular Dystrophy are examined. The classical explanations of a high rate of mutation and heterozygote advantage are shown to be inconsistent with the data. The third hypothesis of two closely linked loci on the X chromosome is developed and shown to be compatible with a set of Utah families including many large Mormon families. The application of the results to other X-linked and autosomal diseases is discussed.